Diffractometer Sample Manipulator for On-Axis Tilt Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing charged-particle diffractometers face challenges in accurately and efficiently positioning small crystalline samples relative to the charged-particle beam, particularly due to gravitational and mechanical constraints, which results in laborious and time-consuming repositioning of the sample, especially when the sample is off-center, complicating electron diffraction tomography.
Innovation Solution
A charged-particle irradiation unit with a manipulator system comprising a rotation stage, first and second translation stages, and a controller, allowing for precise alignment and compensation of gravitational and manufacturing-induced deviations, ensuring the sample's center of mass remains on-axis with the beam axis, even at different rotational positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sample is mounted off-center on the sample holder to accommodate small crystalline samples, then the sample can be positioned within the charged-particle beam, but the sample volume is displaced from the beam axis when changing tilt angles, requiring laborious and time-consuming repositioning
Solution Approach 1:
The patent introduces a second translational degree of freedom (movement perpendicular to the beam axis and rotation axis) in addition to the existing translational movement parallel to the beam axis. This additional dimensional movement capability allows the manipulator to compensate for beam displacement caused by tilt angle changes, maintaining the sample within the beam without requiring manual repositioning for each tilt angle.
Solution Approach 2:
The patent replaces manual mechanical repositioning operations with an automated manipulator system that combines multiple translational stages and a rotation stage. This automated system continuously adjusts the sample position based on the tilt angle, eliminating the need for laborious manual repositioning and reducing the time required for data collection.
2Measurement precision
If manual repositioning of the sample is performed for each tilt angle, then the sample can be re-aligned with the beam axis, but the procedure becomes laborious and time-consuming
Solution Approach 1:
The patent replaces manual mechanical repositioning operations with an automated manipulator system that combines multiple translational stages and a rotation stage. This automated system continuously adjusts the sample position based on the tilt angle, eliminating the need for laborious manual repositioning and reducing the time required for data collection.
Solution Approach 2:
The manipulator system automatically compensates for beam displacement by continuously adjusting the sample position in response to tilt angle changes. The system serves itself by using the known relationship between tilt angle and beam displacement to pre-calculate and execute the necessary position corrections, eliminating the need for operator intervention.
3Manufacturing precision
If the rotation axis is not perfectly aligned with the nominal reference rotation axis, then manufacturing tolerances cause positional deviations, but precise compensation mechanisms are required to maintain positioning accuracy
Solution Approach 1:
The patent incorporates feedback mechanisms where the actual position of the sample is continuously monitored and compared with the desired position. Based on this feedback, the manipulator system automatically adjusts the sample position to compensate for rotation axis misalignment. The feedback loop ensures that even with manufacturing tolerances, the sample remains accurately positioned within the beam.
Solution Approach 2:
The manipulator system is designed with multi-functionality, combining multiple translational stages and a rotation stage in a single integrated unit. This universal manipulator can perform both the primary positioning function and the compensation function for rotation axis misalignment, reducing the need for separate compensation mechanisms and managing device complexity.
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a charged-particle irradiation unit (100) and to a diffractometer comprising such an irradiation unit (100), wherein the irradiation unit (100) comprises a charged-particle source (10), a charged-particle-optical system (20), a sample holder (30) and a manipulator (101) operatively coupled to the sample holder (30) for positioning a sample (31) relative to the beam axis (11). The manipulator (101) comprises a rotation stage (130) for rotating the sample holder (30) with respect to the incident beam around a substantially vertical rotation axis (131), a first translation stage (110) configured to move the sample holder (30) at least along a first sample axis (111) and a second sample axis (112) in a plane perpendicular to the rotation axis (131), and a second translation stage (120) configured to move the rotation stage (130), the sample holder (30) and the first translation stage (110) at least along a first manipulator axis (121) that is perpendicular to the beam axis (11) and perpendicular to the vertical direction. The rotation stage (130) is in a moving system of the second translation stage (120), the first translation stage (110) is in a rotational system of the rotation stage (130), and the sample holder (30) is in a moving system of the first translation stage (110). Thus, the manipulator (101) allows to position the center of mass of the sample (31) substantially on-axis with regard to the rotation axis (131) and to compensate for different rotational positions of the rotation stage (130) a respective measured or pre- determined native deviation of the rotation axis (131) from a position of a nominal reference rotation axis of the rotation stage (130) at least in a direction that is perpendicular to the beam axis (11) and perpendicular to the vertical direction (V).